OBJECTIVE To evaluate the efficacy of plasma sterilization system,observe and comprehend the(methods) and mechanisms of plasma sterilization.METHODS In application of plasma(sterilization) system,the(sterilization) processes were observed.The efficacy of this new system was shown by a biological test and chemical test.Comparative observation was conducted on the effective use time of wire of high-frequency electrode that had been sterilized in plasma sterilization system and Formalin smoke respectively.RESULTS The instrument that had been sterilized in plasma sterilization system all passed the tests and could be used immediately,manipulation of(plasma)(sterilization) system was easy,the effective use times of electrode′s wire were extended.CONCLUSIONS Plasma sterilization system can achieve effective sterilization with low(humidity),and no-toxicity.With shorter sterilization cycle time and lesser damage to surgery instruments,this new system improves the margin of safety and reduces(processing) costs.

Objective To discuss the feasibility of Monte Carlo N-particle transport code(MCNP)simulated calculation.Methods The calculation in water phantom was contrasted with the practical measurements and the reported values using the percent depth dose(PDD)curve and normal peak scatter factor.Results There Was no significant difference between calculated and measured results in the 10 cm×10 cm field(t＝-0.41,P>0.05),however,there were significant differences in the 5 cm×5 cm field(t=7.2,P<0.05)and in the 12 cm×12 cm field(t=-4.6,P<0.05).There was no significant difierence between the calculated results and the reported values(t=-1.91,P>0.05).In the same radiation field,the PDD decreased as the depth increased,but increased as the size of the radiation field increased at the same depth.PDD and normal peak scatter factor were both important parameters for calculation of prescribed dose.Conclusions It is possible to establish a set of accurate and comprehensive percent depth doses and normal peak scatter factor parameters so as to provide the basis of clinical use, quality assurance and quality control for radiotherapy.